New York subway delays have increased this year after decades of underinvestment in the aging system. Spencer Platt/Getty Images

New York's subway system has been under closer scrutiny as disruptions pile up during what many are calling the "summer of hell."

It's hard to go a day without seeing a new complaint about the ailing system on social media. But the frequency of complaints are not just the product of easy access to Twitter: Delays have skyrocketed to 70,000 per month from 28,000 per month in 2012, according to the New York Times.

There are quite a few factors causing the decline in service — scroll down for a closer look:

By the time Moses passed away in 1981, the subway was in dire condition, as reported by Curbed.

Since then, the Metropolitan Transportation Authority has done what it can to keep it operational, but little to bring a century-old system up to modern standards. The MTA even admits that "decades of underinvestment" are to blame for New York's subway woes.

All of this is to say that the state has neglected to channel funding toward longstanding issues. New York Governor Andrew Cuomo and state legislators before him have cut millions in funding in the past, choosing to put money toward other projects.

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Century-old technology

Staff members have to pull handles to operate track switches and signals so operators know it's safe to pass through, Business Insider's Graham Rapier reported. It doesn't give a precise location or speed, so it's hard to tell where the subways are.

The L uses a system known as communications-based train control, which is safer and more reliable. But installing it on every subway line could take 50 years and cost $20 billion, the New York Times reported.

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Overcrowding

Passengers wait inside a stopped C subway train in New York City after a power failure stopped multiple subway lines during the morning commute in New York.
Reuters/Brendan Mcdermid

One might think that using hand signals to control a subway system would be the main force behind delays, but the sheer number of people are actually the biggest problem. Over one-third of delays are caused by overcrowding, Gothamist reported.

Crowding prevents trains from leaving the station on time, a problem that gets progressively worse as the day goes on. New York needs more train cars to handle the swell of people clamoring to ride the system.

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Track fires

The 168th Street subway station became overcrowded after a track fire caused massive delays on July 17, 2017.
Twitter/ Natalie Brito

Track fires have also caused subway delays, but are not the main culprit behind regular disruptions.

Still, they are a headache. A July fire caused major delays along the A, B, C, and D lines, resulting in severe overcrowding in stations and long lines for alternative transit systems, like city buses.

That fire, like many others, was sparked by garbage left on the track.

The agency attempted to combat the issue by launching a five-year pilot program in 2012 that removed garbage cans from subway stations. The thought was people would be encouraged to take their trash out of the station, but the MTA deemed it a failure in March and shut down the pilot, am New York reported.

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Potential solutions

Cuomo walks the tracks in the Columbus Circle subway station in New York during a media tour Wednesday, Aug. 9, 2017.
AP/Richard Drew

The MTA has proposed a few ways to fix these issues.

Cuomo in June gave MTA chairman Joe Lhota 60 days to assess capital needs for cars, tracks, and signals after declaring the MTA was in a "state of emergency."

Lhota is now asking the state to channel $836 million toward short-term solutions like increasing the length of trains, cleaning stations, and adding personnel. The MTA is then requesting an additional $8 billion for long-term repairs that would allow the agency to modernize the overall subway system.

How the state will pay for the costly repairs remains to be seen.

Cuomo is putting together a congestion pricing plan, which has previously failed to gain traction with the State Legislature, to fix New York's growing traffic problem and pay for subway repairs, the New York Times reported.